[awk] Tab separated values in awk

How do I select the first column from the TAB separated string?

# echo "LOAD_SETTLED    LOAD_INIT       2011-01-13 03:50:01" | awk -F'\t' '{print $1}'

The above will return the entire line and not just "LOAD_SETTLED" as expected.

Update:

I need to change the third column in the tab separated values. The following does not work.

echo $line | awk 'BEGIN { -v var="$mycol_new" FS = "[ \t]+" } ; { print $1 $2 var $4 $5 $6 $7 $8 $9 }' >> /pdump/temp.txt

This however works as expected if the separator is comma instead of tab.

echo $line | awk -v var="$mycol_new" -F'\t' '{print $1 "," $2 "," var "," $4 "," $5 "," $6 "," $7 "," $8 "," $9 "}' >> /pdump/temp.txt

This question is related to awk

The answer is


Use:

awk -v FS='\t' -v OFS='\t' ...

Example from one of my scripts.

I use the FS and OFS variables to manipulate BIND zone files, which are tab delimited:

awk -v FS='\t' -v OFS='\t' \
    -v record_type=$record_type \
    -v hostname=$hostname \
    -v ip_address=$ip_address '
$1==hostname && $3==record_type {$4=ip_address}
{print}
' $zone_file > $temp

This is a clean and easy to read way to do this.


Make sure they're really tabs! In bash, you can insert a tab using C-v TAB

$ echo "LOAD_SETTLED    LOAD_INIT       2011-01-13 03:50:01" | awk -F$'\t' '{print $1}'
LOAD_SETTLED

You can set the Field Separator:

... | awk 'BEGIN {FS="\t"}; {print $1}'

Excellent read:

https://docs.freebsd.org/info/gawk/gawk.info.Field_Separators.html


Should this not work?

echo "LOAD_SETTLED    LOAD_INIT       2011-01-13 03:50:01" | awk '{print $1}'

echo "LOAD_SETTLED    LOAD_INIT       2011-01-13 03:50:01" | awk -v var="test" 'BEGIN { FS = "[ \t]+" } ; { print $1 "\t" var "\t" $3 }'